Re: [ANNOUNCE][CFT] kexec for v2.5.48 && kexec-tools-1.7 -- Success Story!

Suparna Bhattacharya
2002-11-20T11:51:58Z

On Wed, Nov 20, 2002 at 02:17:04AM -0700, Eric W. Biederman wrote:
> Suparna Bhattacharya <suparna@in.ibm.com> writes:
>
> > On Mon, Nov 18, 2002 at 05:10:38PM -0800, Andy Pfiffer wrote:
> > > On Mon, 2002-11-18 at 00:53, Eric W. Biederman wrote:
> > > > kexec is a set of systems call that allows you to load another kernel
> > > > from the currently executing Linux kernel. The current implementation
> > > > has only been tested, and had the kinks worked out on x86, but the
> > > > generic code should work on any architecture.
> > >
> > > Great News, Eric. For the first time *ever* I got a kexec reboot to
> > > work on my most troublesome machine (see below).
> >
> > Same here - preloading the new kernel and issuing kexec -e after
> > init 1 works on the troublesome SMP system I'd earlier been sending
> > you earlier. Bootimg used to work on this setup, so bypassing the
> > bios calls had the expected effect.
> >
> > If I issue the call earlier though, it runs into trouble with aic7xxx
> > reporting interrupts during setup. Guess you know why we are looking
> > at that case - eventually need to be able to transition directly at dump
> > time without a chance to go through user-space shutdown ...
>
> The needed hooks are there. You can make certain an appropriate
> ->shutdown()/reboot_notifier method is present, or you can fix the driver
> so it can initialize the device from any random state.
>
> I really don't know what kinds of failures you hope to recover
> from with the kexec on panic code, so I really can't comment on
> how well things will work. There will always be a set of failures
> that are non-recoverable, but that doesn't mean there isn't a useful

I agree. If we can get as far with this for situations in which
mcore with bootimg worked (but then we never did try that on
2.5 and am not sure if it was using the current aic7xx driver) that
would be a lot - handling of more difficult cases can
happen bit by bit after that. Whatever can be covered is useful even
if it doesn't address all kinds of troublesome situations.

> subset. Anyway there is certainly plenty of material for you to
> experiment with and see what works usefully in practice.

Yes there is, thanks :)

Regards
Suparna

>
> Eric
>

--
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Labs, India